CHAPTER II. 



PACT OF VARIATION. 



It is scarcely possible to survey the members of the 

 external world around us without being struck with the 

 instability with which everything is impressed. The 

 very shadows^ as they pass^ leave a moral lesson behind 

 them on the moimtain-slope, which the student of 

 Nature would do well to contemplate. Whatever be 

 our preconceived ideas of the " immutability of the uni- 

 verse," from first to last the same truth is re-echoed to 

 our mind, — that here all is change. Organic and in- 

 organic matter are alike subjected to renovation and 

 decay ; and, dependent on that general law, variability 

 withiu specific limits would seem to be an almost neces- 

 sary consequence. In the animal and vegetable king- 

 doms, this priaciple of fluctuation is peculiarly apparent ; 

 and not more surely do the winds of heaven ruffle the 

 forests over which they rage, than does the ebb and flow 

 which is perpetually goiug on amongst created things 

 mar their boasted constancy. 



The fact of aberration, to which we would briefly 

 allude in this chapter, requires but little comment ; it is 

 patent a priori. As a matter of experience, every ob- 

 server who has spent a week in the field of Nature 



